Outer Limits 4x4 Board

As the subject says.
What do you guys think the biggest tyre you can run on standard chassis WT Sierra without it getting to tippy on steep hills? 31? 32?

Cheers

at the moment ive got 2 inch spring lift, 1 inch shackle lift. Maybe virtual lift to come.

tippy what do you mean by that? Side ways roll or endo or what?

they'll be fine. its not the tire that makes you tip, its the driver that does that. drive to the conditions and you wont be visiting the flip side very often.

Tippy as in end over end...

Swamp Donkey - I realise that, but obviously there comes a point where the vehicle can no longer handle an angle and decides it wants to roll down the hill backwards.
Im not after a specific angle as I know there are to many variables just a rough idea?

32 imho would be tops u can really tell the diff in the ride aswell, in the the shorty zook ur limited to how steep a hill u can climb before goin over, i no ive come close a few times , thats why i got a lwb now and the difference speaks for its self.

there is a guy in the vic zook club running Q78's (35.5) on a standard wheelbase (ruf) obviously those tyres are not effective as they could be on a lwb but they seem to work. He is running the car very low only 2inch suspension lift springunder and a 2 inch body lift.
Im not sure how it compared to the swb zooks on adventure tour with 32-33" tyres on them. Ive seen gregs swb sierra with 33" swampers drive some great lines and never look unstable.

when you go past 31's any way you gotta put gears and stuff in anyways because the ratio is too high

ofr57 wrote:when you go past 31's any way you gotta put gears and stuff in anyways because the ratio is too high

so what

I run 32' swampers on my swb, its wb isnt much over standard, only a few inches longer. I wouldnt go any bigger, have come close heaps to going arse over breakfast even crawling in low 1st. Though your driving style can be an influence. Heaps of throttle will make you go over before crawling will often.

Layto....

There is a lot more to consider than "getting tippy".
Why do you want big rubber?
By standard chassis do you mean without moving diffs?
How much panel do you want to remove?
Do you plan to stick with 2" spring, 1" shackle?
Is body lift out of the question?
Have you considered the important factors like drivetrain (ref ofr57 TC gears) CVs, diffs, etc
What other modifications are allowable?
Will this be engineered (legal!!)?
Will you brakes handle this?

If you have a carby you will stall before you reach a vertical position, so the tyres are not a consideration. Which if you could get near vertical heavy tyres (lowest point of vehicle) would actually be an advantage as it compensates for your weight (highest point of vehicle).


If you just want big rubber for poser value, the length of the wheelbase is your maximum diameter (beyond that the front wheel rubs on the rear )

If you are looking for a performance improvement, stick with a good set of 31" tyres (which should fit your Zook now with your existing set-up), any $$$ you have left invest in reduction gears. Without them you are unlikely to have the ability to get up anything steep enough to flip.

The best advice I have ever read on this forum has been to learn to drive your vehicle to it's current limits, in doing so improve your driving skill so that you UNDERSTAND any modification you may consider. This will save you $$$, frustration, embarassment and injury.

Sorry if I come off sounding like a grumpy old fart, but have you really thought any of this through?

DiddyZook wrote:There is a lot more to consider than "getting tippy".
Why do you want big rubber?
By standard chassis do you mean without moving diffs?
How much panel do you want to remove?
Do you plan to stick with 2" spring, 1" shackle?
Is body lift out of the question?
Have you considered the important factors like drivetrain (ref ofr57 TC gears) CVs, diffs, etc
What other modifications are allowable?
Will this be engineered (legal!!)?
Will you brakes handle this?

If you have a carby you will stall before you reach a vertical position, so the tyres are not a consideration. Which if you could get near vertical heavy tyres (lowest point of vehicle) would actually be an advantage as it compensates for your weight (highest point of vehicle).


If you just want big rubber for poser value, the length of the wheelbase is your maximum diameter (beyond that the front wheel rubs on the rear )

If you are looking for a performance improvement, stick with a good set of 31" tyres (which should fit your Zook now with your existing set-up), any $$$ you have left invest in reduction gears. Without them you are unlikely to have the ability to get up anything steep enough to flip.

The best advice I have ever read on this forum has been to learn to drive your vehicle to it's current limits, in doing so improve your driving skill so that you UNDERSTAND any modification you may consider. This will save you $$$, frustration, embarassment and injury.

Sorry if I come off sounding like a grumpy old fart, but have you really thought any of this through?

what evidence is there that he hasn't considered what else it will take to run large tyres? mistaboz is not a new member.
What your suggesting isnt anything new on this forum. Of course there are other considerations when running larger rubber, however this tells us nothing about the relationship between wheel base, tyre diameter and stability of a car.

To narrow the question, Is the diameter of the tyre relavant at all? or is it the extra height, and importantly extra traction, (the car will now drive to a more scary angle) that is making the car feel more unstable.

mistaboz wrote:Tippy as in end over end...

Swamp Donkey - I realise that, but obviously there comes a point where the vehicle can no longer handle an angle and decides it wants to roll down the hill backwards.
Im not after a specific angle as I know there are to many variables just a rough idea?

i'v been up on my spare heaps of times. you have to get up on some serious angles to go over backwards. besides that, in my experience if you do go over backwards and you have spare on it will fall on to its side.. it dont matter what size tire you got if you divin up stuff that steep, if you goin over, you goin over.

you can go as big as you like but if you dont have the correct gearing itll suck

id go to a 31-32 max until you get some gears and some wheelbase

Yes I have thought about all my possibilities DiddyZook
I have taken into concideration everything that you have mentioned before you even mentioned it. Thanks for the info anyway

If I am going to be getting 31's or 32's it will be with gears as well.
I dont use my zook as a poser, hell it's not even a daily driver. Just used to get my from home to the bush. All my modifications are used for the purpous (spelling) they are meant for.

Body lift is also out of the question, as is removing panels.

The idea of larger rubber was to give me more diff clearence.
Only thing that sux is the width of 10.5 on a 15x7 rim. Will be hitting the springs on the front. I dont really want to extend my bumpstops so am allowing for the fact I may have to move some metal into the engine bay a little more.

By the sound of it I might stick to some agressive 31's and some gearing and see how I go from there.

Thanks for all the replies and constructive criticism

Relocating your front axle an inch or so by redrilling the spring or spring plate or both i would run up to a 33.

If your mainly off road you could do this for no $$ and then get your bigger meats under without too much effect on stability. If you found it a bit tippy then you could do the same to the rear.

Just my thoughts though.

If your tyres hit the springs on the front then offset them.

CanberraMav - I thought of doing this a few months ago. Wont it mean though that the tyre hits the headlight bucket?

A 33" probably will with the lift you described. If your prepared to do a virtual lift as described then you should fit them in ok. Generally the scrubbing issues are on the back of the front wheel arch.

If i were you i would borrow a 33 and put it on the front and play around with the position of the axle. You dont want to move it too far forward. You may need to put in a body lift.

mistaboz wrote:CanberraMav - I thought of doing this a few months ago. Wont it mean though that the tyre hits the headlight bucket?

yes it will

So maybe I need to do a virtual lift and redrill the spring perch 20mm or there abouts to fit a 32?
When redrilling the spring perch do the ubolts still hold the springs to the axle ok?

They hold fine.
you can also make/buy relocation plates. I think maybe nicbeer or alien posted some photos at some stage.

i run 33" swampers , front diff moved forward , about 1.5-2" !!!
rear diff moved back about 1" !!
body lift , 4"(dont ask !! )

never had falling over backwards problems !!
never had tyre hitting headlight bucket problems !!

& i can flex up so the tyre is all the way in the gaurd !!!!!!(must make those front bumpstops bigger , 1 day !!)

don't you have a shackle reversal too Moose which would cause the tyre to stuff into the guard in a very different place

Well I put mine over all the time, sideways. Never endo'd but have come close.
IMO its not the tyre size, its the lift on a shorty that causes the end-end roll probs.
We recently stretched my brothers lux-diffed coily to 95"WB for this reason as it sat about 10" over standard at stock WB it didn't take much at all for him to wheel stand it, and send it over backwards.

i ran 34" jt2s on standard swb - it was hectic

moose ya got to drive it before attempting to roll it....

Great, thanks for the replies everyone.
Will slowly keep modifying it and see what I come up with.

Cheers Paul

bazooked wrote:moose ya got to drive it before attempting to roll it....

went out couple weeks ago !!!!

N*A*M wrote:i ran 34" jt2s on standard swb - it was hectic

spoa?

muppet_man67 wrote:

N*A*M wrote:i ran 34" jt2s on standard swb - it was hectic

spoa?

Pretty sure he had standard suspension, with a guard chop and i think a 2" BL.

That would be a pretty good cog with 2 inch lift and guard chop with 34's.
I think it would attract the unnecesary people more than a set of 31's or 32's would though.